The invention relates to an auxiliary device for an agricultural working machine. Such an agricultural auxiliary device can be, for example, a combine-mounted device or a non-self-propelled, drawn agricultural machine such as a self-loading forage wagon or a swather. The self-propelled agricultural working machine is designed, in particular, as a tractor or a similar towing machine, without limitation.
Auxiliary devices for agricultural working machines are known. For example, document DE 695 13 718 T2 makes known a rotary swather as an auxiliary device for an agricultural working machine such as a tractor. The rotary swather comprises a hydraulic drive in the form of a hydraulic motor for driving a rotor. The rotary swather also comprises a dedicated hydraulic pump unit designed to pump a hydraulic fluid at a predetermined working pressure. In this case, the hydraulic motor is fluidically connected to the hydraulic pump unit disposed on the rotary swather via two hydraulic lines in order to supply the hydraulic motor with hydraulic fluid under working pressure and, to carry away the hydraulic fluid that is output by the hydraulic motor.
Such known auxiliary devices having a hydraulic drive are usually operated in the open hydraulic circuit. The resultant hydraulic heat loss is reflected in the warming of the hydraulic fluid (such as hydraulic oil, for example). In order to limit the temperature of the hydraulic fluid to a permissible temperature level, such hydraulic circuits have large tank volumes and surfaces or a cooler for the hydraulic fluid. Due to the large tank volumes and the hydraulic fluid contents thereof, the production costs are increased and high service costs result over the service life of the product. A cooler for the hydraulic fluid also requires a cooler drive, which is susceptible to contamination and also results in higher service requirements.